Well, 2 actually...
For starters, it's creating a file in "...\Temporary Internet Files\Content.IE5\RANDOMFOLDERNAME\isd2update.upt," and judging by the filename is pretty traceable.
Also, I was looking through the options, and studying them more carefully, and it seems to me that a little ignorance on the user's part can make the app less portable (running on startup, of course, but also allowing the user to set boottime defrag, and allowing the user to shut down the computer automatically when defragmenting is over...)
I'm honestly not sure about continuing this app, if not for the first reason, then definitely for the second. I can contact the devs to see if we can work something out, though.